Which one of the following forms a vortex ring?
(A) ${{P}_{2}}{{O}_{5}}$
(B) $P{{H}_{3}}$
(C) $N{{H}_{3}}$
(D) ${{P}_{4}}{{O}_{10}}$

Hint: Out of the given compounds, the one which forms vortex rings reacts with oxygen gas to produce that. These compounds undergo oxidation reaction in presence of oxygen gas to form vortex rings.

Complete step by step solution:
Here, we are being asked which of the given compounds can form a vortex ring upon its reaction with another compound.
-Vortex ring is also called toroidal vortex which has a torus-shaped ring. This type of ring is seen in the fluids. Fluids involve liquids and gases. Thus, the vortex ring is a ring where the fluid spins around an imaginary axis which forms a loop.
-There are certain smoke rings produced that show the above-mentioned properties. Let’s see which compound will give a vortex ring.
-Out of all the given compounds, Phosphine ($P{{H}_{3}}$ ) can produce vortex rings. They are produced when phosphine gas reacts with oxygen gas. The reaction is given below.
\[2P{{H}_{3}}+4{{O}_{2}}\to {{P}_{2}}{{O}_{5}}+3{{H}_{2}}O\]
So, this is a redox reaction. Here, the phosphorus atom in the phosphine gets oxidized and oxygen gets reduced.
-The resultant gas Phosphorus pentoxide (${{P}_{2}}{{O}_{5}}$ ) forms vortex rings.
-These vortex rings are used in the preparation of smoke screens in warfare.

Thus, we can say that correct answer of this question is (B) $P{{H}_{3}}$.

Note: Remember that phosphorus pentoxide gas is there in the composition of the vortex ring but it is not used as a starting material for the production of vortex rings. Instead, phosphine gas is used as a starting material to produce phosphorus pentoxide.